This invention relates to a hood assembly for a mobile excavator.
For the swivelling of hoods on vehicles, lever arrangements are known (German Patent Document DE-PS 915781) which cause an opening and closing of a hollow space in the vehicle body by way of the hood.
It is an object of the invention to provide a hood for a mobile excavator which, for the swivelling by way of the lever arrangement, carries out a precisely coordinated movement in a defined swivel area.
According to the invention, this object is achieved by providing a hood assembly for a mobile excavator comprising:
a hood arranged behind an excavator driver's cab, as considered in a forward excavator driving direction, said hood having a first forward end wall which faces the driver's cab and a second forward end wall set back rearwardly of the first forward end wall to form an offset area to accommodate an offset section of the driver's cab, said first and second forward end walls being disposed in respective substantially parallel planes extending obliquely toward the rear at an acute angle with respect to the local horizontal when said hood is in a closed in-use position, PA1 a pair of exterior side levers and a center lever pivotally connected to the hood and to relatively fixed excavator parts and serving to controllably support the hood for movement between a closed position and an open position, said levers and said hood together forming a four bar linkage by way of which lower boundary edges of the first and second forward end walls during the swivelling in the overlapping area with the driver's cab and a tank can be moved within a gap as well as along a front wall of the tank on a straight course along the planes.
The principal advantages achieved by means of the invention are that the hood, which has a set off in the area facing the driver's cab, is arranged so that during the swivelling in the case of a movement, it is free of the driver's cab and of the fuel tank to be covered. The reason is that one end wall of the hood is arranged in an area in a gap between the driver's cab and a hydraulic-oil tank and the additional connecting end wall is arranged to cover a fuel tank.
So that, on the one hand, during the swivelling, a lower hood edge of the end wall will not be wedged in the gap and, on the other hand, the additional hood edge of the other end wall will not strike against the fuel tank, a straight-line motion will take place in a first swivel range of the hood which will be followed by a curved swivel motion of the hood or the hood edge.
For achieving corresponding guided swivel motions, a special lever arrangement is provided which consists of two outer side levers and one center lever arranged in-between which is connected with a pneumatic spring. Together, the levers form a four-bar mechanism, the hood representing the connecting rod.
The side levers are arranged directly adjacent to the interior surface of the hood and above the hydraulic-oil tank and are placed by means of a bent rearward end against a bearing bracket of the vehicle body. The center lever extends approximately as an extension of the side levers and is held in a bearing bracket behind the bearing brackets of the side levers. Between the bearing brackets of the side levers and the bearing bracket of the center lever, the pneumatic spring is supported on the vehicle body.
The pneumatic spring is designed in such a manner that, in a first swivel range, the hood will lift automatically. In an intermediate swivel range, the center position of the center of gravity is overcome manually by way of the pivot of the center lever on the vehicle body. In the case of the end swivel range, the pneumatic spring promotes the hood movement to such an extent that a slow damped lowering of the hood takes place over the rearward structure of the vehicle.